Cover for an engine



FIG. 1 is a top view of a cover for an engine showing our new design;

FIG. 2 is a bottom view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a rear view thereof; and

FIG. 6 is a front view thereof. 

The ornamental design for a cover for an engine, as shown and described. 